More people live in China than any other country, and in 2010 it surpassed the United States as the largest car market on Earth. As the popularity of automobiles grows, China's infrastructure has struggled to keep pace.

The result is -- like anywhere else in the world -- traffic jams.

Yet traffic jams in China are not always brief hiccups during the evening commute. In fact, the worst jams in China, while rare, can last for days.